1. Field of the Invention
The invention relates generally to wiring components of relocatable wiring systems and particularly to devices and cables connecting the wiring components of the system for distributing three-phase power to loads.
2. Description of the Prior Art
Electrical wiring for operating lighting fixtures and other circuit loads has long been an art practiced in a variety of similar, basically simple ways. The various forms of “hardwiring” constitute the bulk of present day wiring methods. “Hardwiring” methods typically involve installation of conduits with wire or cable then being pulled through the conduit. In the case of lighting fixtures, these fixtures must then be hung and connected to the electrical system within the conduit so that the fixtures can then be energized. These prior practices require substantial labor costs which typically account for seventy to eighty percent of total electrical installation job cost.
Prior wiring systems installed by this conventional “pipe and wire process” has the additional disadvantage that it cannot be used for temporary lighting during facility construction and again for permanent lighting since those materials used in hardwiring processes are usually not reusable. Further, circuitry changes due to layout revision or expansion cannot readily be accommodated in prior art hardwiring systems due to a typical inability when using such prior art systems to reuse those materials which have been cut, such as conduit, for a dedicated circuit arrangement. Relocation of lighting fixtures or other electrical loads in the prior art hardwired systems is thus virtually impossible, it usually being necessary to begin the wiring process anew when fixture relocation is necessary. Prior art hardwiring systems also require that a number of different structural elements be kept in inventory, these structural elements including conduit, wire, couplings, connectors, wirenuts and other miscellaneous materials.
Those disadvantages inherent in conventional hard-wiring processes are generally obviated through the employment of wiring systems known particularly in the industrial and commercial lighting fields by the mark RELOC™ which is a trade-mark of Lithonia Lighting, Inc., a Division of Acuity Brands, Inc. of Atlanta, Ga. The manufactured wiring systems marketed under the mark RELOC™ facilitate the construction of industrial and commercial installations through the provision of plug-in, relocatable, modular components suitable for commercial wiring, industrial wiring, access floor wiring, local switching, and power applications. The primary benefits of the RELOC™ manufactured wiring systems include reductions in installation time and labor costs as well as easy fixture relocation. Use of these premanufactured relocatable wiring systems can provide labor savings of approximately 75% and total job cost reductions of approximately 25%. The RELOC™ systems also require a minimum number of inventory components which components can be manufactured with high quality control in a manufacturing facility to meet or exceed the requirements of UL, the National Electrical Code, and CSA.
The process of installation of the RELOC™ system requires only a single pass along each branch circuit or row of fixtures in order to install the system and to hang fixtures. The time required for a RELOC™ installation is therefore a fraction of the time necessary for conventional hardwiring systems. Industrial HID fixtures can be installed in a typical warehouse lighting application with substantial labor savings, job labor content using hardwiring processes typically being the highest percentage of a total job cost. Additionally, the RELOC™ system can be used for temporary lighting during facility construction and again for permanent lighting. Fixtures can be easily relocated and circuitry changed due to layout revision, expansion or for other reasons through the use of the RELOC™ wiring system. The RELOC™ wiring system can include a circuit selector associated with lighting fixtures which allows the fixtures to be connected to a particular circuit of a plurality of circuits which are contained within cable which is plugged together through the use of female connector heads and male connector heads located at opposite ends of discrete lengths of cable. These discrete lengths of cable are plugged together to form a desired branch circuit length. Exemplary circuit selection devices are described in detail in U.S. Pat. No. 5,679,016 to Marder et al. and U.S. Pat. No. 5,679,023 to Anderson et al., the disclosures thereof being incorporated by reference herein in their entirety. Other exemplary components of the RELOC™ wiring system are described in detail in U.S. Pat. No. 5,819,405 to Marder et al., U.S. Pat. No. 6,083,053 to Anderson, Jr. et al., U.S. Pat. No. 6,102,733 to Anderson, Jr. et al., U.S. Pat. No. 6,113,435 to Anderson, Jr. et al., U.S. Pat. No. 6,126,490 to Anderson, Jr. et al., the disclosures thereof being incorporated by reference herein in their entirety.
The present invention improves upon the prior art by the provision of a relocatable manufactured wiring system that provides for load balancing and that is relatively inexpensive and more easily manufactured when compared to the structures of the prior art.